1. Field of the Invention
The present invention relates generally to compositions for decontaminating surfaces and methods of using such compositions to decontaminate surfaces. More particularly, the present invention relates to clay-based compositions and methods of using such clay-based compositions to decontaminate a surface and/or a material having a surface.
2. State of the Art
Radioactive, biological, and other unwanted contaminants may adhere to surfaces or penetrate into porous materials upon exposure of the material to such contaminants. Often times, contamination resulting from such exposure is hazardous and must be removed in order to make the material safe for its intended use.
For example, materials and surfaces coming in contact with radioactive materials for the production of energy, production and use of radioactive medical devices, and the disposal of radioactive waste often become contaminated with radioactive materials that contact such surfaces. Human exposure to the resulting radioactive contamination on the surface of such materials is undesirable; therefore, contaminated surfaces and materials must be decontaminated before further use or they must be disposed of.
In addition, the increased availability of radioactive and bioactive materials has increased the probability that a “dirty-bomb” utilizing such materials may be used as a weapon for terrorist acts or in low-conflict warfare. If employed, weapons utilizing radioactive materials or bioactive materials would cause the spread of radioactive or bioactive contamination within a zone of activation. Materials, such as building materials, exposed to the radioactive or bioactive contamination would become contaminated. In order to safely decontaminate the exposed materials and surfaces, suitable and effective decontamination methods and compositions would need to be employed.
Although numerous methods and compositions may exist for removing radioactive contamination or bioactive contamination, many of the decontamination methods are costly or are destructive of the materials being decontaminated. For instance, concrete exposed to radioactive contamination may be decontaminated using active chemical agents and physical scrubbing techniques. Typically, concrete or other porous surfaces contaminated by radioactive materials are decontaminated by physical grit blasting of the surface of the contaminated material and chemical treatment of the surface. Costs associated with such decontamination methods are high, the amount of waste generated by such methods is large, and the waste must be specially disposed of due to the radioactive and hazardous nature of the waste. In addition, such decontamination processes are labor intensive. Further, grit blasting and chemical treatments usually only decontaminate the surface of a material and are rarely capable of treating the bulk of a material or a significant distance beyond surface contamination, if deeper contamination exists.
Therefore, it is desirable to develop methods for decontaminating surfaces exposed to radioactive contamination, bioactive contamination, or other forms of contamination. It is also desirable to provide decontamination compositions that may be used to decontaminate surfaces and sub-surfaces of materials that have been exposed to radioactive, bioactive, or other contaminants.